Blower and fan wheel apparatus

ABSTRACT

The invention is a fan and blower wheel having hollow annular counterbalance chambers concentric with a central drive shaft. Initial counterbalancing is accomplished by filling one or more of the chambers with a liquid thermosetting plastic containing heavy and light fillers. The fillers segregate under the force of rotation and are hardened in place. Final counterbalancing for dynamic vibrations and for future inbalance caused by dirt build up, corrosion or abrasion is accomplished by partially filling one or more of the remaining concentric annular counterbalance chambers with a dense fluid which is free to move. Preferably, the dense fluid also includes high density material such as lead shot or ball bearings.

United States Patent: 1 [111 amaazo Huntington .131 10, 11973 BLOWER ANDFAN WHEEL APPARATUS [76] Inventor: Richard L. Huntington, Route 1,

Van Buren, Ohio [22] Filed: May 11, 1971 [21] Appl. No.: 142,183

[52] US. Cl. 416/145 {51] Int. Cl. F0401 29/00 [58] Field of Search416/144, 145

[56] References Cited UNITED STATES PATENTS 2,323,637 7/1943 Wiiliams416/144 X 2,340,427 2/1944 Putt 416/144 2,576,105 11/1951 Childs 416/145X 2,722,848 11/1955 Stein 416/144 X 2,771,240 11/1956 Gurin 4. 416/1453,323,597 6/ 1967 Longobardi et a1. 416/ 144 3,586,460 6/1971 Toner416/144 1,684,773 9/1928 Marks 416/144 UX Primary Examiner-Everette A.Powell, Jr. A20mey0wen and Owen I 57} ABSTRACT The invention is a fanand blower wheel having hollow annular counterbalance chambersconcentric with a central drive shaft. Initial counterbalancing isaccomplished by filling one or more of the chambers with a liquidthermosetting plastic containing heavy and light fillers. The fillerssegregate under the force of rotation and are hardened in place. Finalcounterbalancing for dynamic vibrations and for future inbalance causedby dirt build up, corrosion or abrasion is accomplished by partiallyfilling one or more of the remaining concentric annular counterbalancechambers with a dense fluid which is free to move. Preferably, the densefluid also includes high density material such as lead shot or ballbearings.

9 Claims, 6 Drawing Figures Patented July 10, 1973 3 Sheets-$lmet lPatented July 10, 1973 3 Sheets-Sheet 2 FIE-4L IN VEN I'UR: FMHARD L.HUNTING TUN.

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Patented July 10, 1973 3,744,929

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BLOWER AND FAN WHEEL APPARATUS BACKGROUND OF THE INVENTION Plastic axialfans and centrifugal blowers commonly in use must be dynamicallybalanced at or close to operating speed and load due to the low modulusof elasticity of plastics which deflect and stretch when subject tovarying centrifugal and load forces. For example, the modulus ofelasticity of fiberglass reinforced plastic is on the order of l X psias compared to 3 X 10' psi for steel. The relative densities are on theorder of 1.8 gm./cm. for fiberglass reinforced plastics as compared to7.0 gin/cm. for steel. A comparison of the densities and elasticities ofsteel and reinforced plastic indicates that stretch due to non-uniformcentrifugal force due to non-uniform plastic blade members would beapproximately seven times that for a steel counterpart.

Prior art plastic fan and blower wheel inbalance has often resulted inexcessive vibrations, noise and excessive tensile stresses which requireexcessive safety factors and over design. Because of these problems inprior art plastic fan and blower wheels, either the fan and blowerwheels were often unsatisfactory or they were used only for secondaryuses where the porblems were not critical.

SUMMARY OF THE INVENTION This invention relates to a blower and axialfan design for air pollution control and, more particularly, to animproved counterbalanced fan and blower wheel.

Blower and axial fan wheels, according to the present invention aredynamically counterbalanced during operation by including one or moreannular concentric hollow ring-shaped compartments in the rotatingmember. The hollow ring-shaped compartments are partially filled with adense fluid which is free to move and counterbalance centrifugal andoperational forces.

Fan and blower wheels are initially permanently counterbalanced byfilling one or more of the annular ring-shaped compartments with aliquid thermosetting plastic containing both a dense and low densityfiller. The fillers are segregated in place by centrifugal force byrotation at design speeds, and the plastic catalyzed in place during theinitial balancing operation.

A counterbalancing dense fluid is added to the remaining annularcompartments to counterbalance any dynamic imbalance and to dampen orreduce any vibrations.

It is, therefore, an important object of this invention to provide axialfan and blower wheels of improved design, capable of operating at highspeeds and efficiency levels while simultaneously operating at lowvibration and noise levels.

It is an important object of the present invention to provide qualityaxial fan and blower wheels constructed of plastic which can be producedin large quantities at a comparatively low cost.

Another object of the present invention is to provide fan and blowerwheels which can handle corrosive gases containing air pollutants whichwill not go out of balance due to corrosion, dirt build up, abrasion andvariations in speed, which are safe and require a minimum in maintenancecosts.

Still additional objects, benefits, and advantages of this inventionwill become evident from a study of the following detailed descriptiontaken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a front view of acentrifugal blower wheel showing blade, annular ring and hub placement;

FIG. 2 is a sectionai top view taken slong the line 2-2 of the blowerwheel shown in FIG. ll;

FIG. 3 is a front view of another embodiment of an axial fan wheelshowing blade, annular ring and hub placement;

FIG. 4 is a sectional top view taken along the line 4-4 of the fan wheelshown in FIG. 3;

FIG. 5 is a front view of another embodiment of a fan wheel having aperipheral blade annular counterbalance ring; and

FIG. 6 is a sectional top view taken along line 66 of the fan wheelshown in FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. I and 2, ablower wheel according to the present invention is generally indicatedby the reference number 15. Preferably, the blower wheel is constructedof plastic. The blower wheel 115 includes an annular gas inlet facemember 16, a disk-shaped back plate 17, a central reinforcing member I8which supports interposed radial blades I9 and an axial drive shaft 20.

The annular gas inlet face member 16 includes a hollow annular-shapedchamber 21 around its periphery. Similarly, the disk-shaped back plate17 includes a ho]- low annular chamber 22 around the periphery of saidplate.

A central V-belt pulley 23 is affixed to the back plate 17 withfasteners 24. A pulley cover plate 25 forms a hollow annular chamber 26with the pulley 23 and the back plate 17. An annular shaft shroud 27extends rearwardly from the back plate 17 and surrounds the shaft 20.

The blower wheel T5 is initially balanced by mounting the blower wheelin a horizontal position, filling the central annular-shaped chamber 26with a thermosetting resin and a filler of, for example, a powdered leadand hollow spherical particles, for example, saran microballoonparticles and rotating the blower wheel at the desired operating speeduntil the resin sets, thereby affixing the filler counterbalance. Thethermosetting resin is thrown outwardly to the periphery of the annularring effectively counterbalancing vibrational forces while the lightersaran microballoons are displaced toward the center of the annular ring.The thermosetting resin and filler also reinforces the center of theback plate 17. Either polyester resins or, for example, epoxy resins maybe used. Neither polyester nor epoxy thermosets require outside heat orpressure to achieve a permanent set. These thermosets react at roomtemperature to create tightly crosslinked chain structures.Characteristics and types of thermosets are well known to the art (seel969l970 Modern Plastics Encyclopedia). Other types of fillers may alsobe utilized, for examples, barium sulfate or barium oxide.

The annular chambers 21 and 22 are partially filled after the initialcounterbalancing operation with a suitable dense fluid such as oil,mercury or a slurry of lead oxide in oil. Preferably lead shot, ballbearings, powdered lead, or similar dense material is included with themercury or oil, with the dense material free to position itself aroundthe periphery.

In operation, the counterbalance fluid is distributed around theperiphery of the counterbalance annular chambers 21 and 22 bycentrifugal force and serves to counterbalance operational forces aswell as to dampen vibrational forces. The dense material tends toestablish its center of gravity opposite the heavier, imbalancing areaof the blower wheel 15.

Referring now to FIGS. 3 and 4, an axial fan wheel according to thepresent invention is generally indicated by the reference number 30. Thefan wheel 30 includes blades 31, a central hub 32 mounted on a centralshaft 33 and a shaft cowling 34. A double V pulley 35 is mounted on theshaft 33 and is embedded in plastic to form the hub 32. The pulley 35and the cowling 34 define annular counterbalance chambers 36, 37, and38.

Initial fan balancing in this design is achieved by mounting the fan ina horizontal position, filling the central compartment 36 with resincontaining powdered lead filler and saran microballoons, and rotatingthe wheel at the desired balancing speed until the resin has set. Theouter annular counterbalancing chambers 37 and 38 are then partiallyfilled with a dense: counterbalance fluid.

Referring to FIGS. and 6, an axial fan wheel, ac cording to the presentinvention, is generally indicated by the reference number 40. The fanwheel 40 includes a hollow annular peripheral chamber 41,interconnecting radial fan blade 42 and a central hub 43. The hub 43includes a V belt pulley 44 mounted on a central drive shaft 45. A shaftcowling 46 and the pulley 44 defines annular and counterbalance chambers47 and 48.

The fan wheel 40 is initially counterbalanced by adding a thermosettingplastic, containing a dense and light filler to one or more of thecentral annular compartments 47-48 and rotating at operational speedsuntil the plastic has set. The annular counterbalance chamber 41 is thenpartially filled with a dense fluid. As mentioned above, thethermosetting resin may be either a polyester resin or an epoxy resin.Suitable dense fillers are, for examples, powdered lead or iron filings,while the light filler may be, for examples, saran mircoballoonparticles or wood particles.

While the invention has been described with particular reference to theembodiments shown in the drawings, many changes may be made in thedetailed construction to accommodate variations in the method ofmanufacture. It shall be understood that such changes shall be withinthe spirit and scope of the present invention as defined by theappending claims.

What I claim is:

l. Blower and fan wheel apparatus comprising in combination, a hubhaving an axis of rotation, a circular back plate attachedto said hub, acover plate attached to said hub and to said back plate, said coverplate, said back plate and hub defining an annular central chamberconcentric to such axis of rotation, such chamber being at leastpartially filled with a thermoset resin, a high density filler and alower density filler, a circular face member spaced from said rearplate, a plurality of interconnecting radially positioned blades mountedbetween said back plate and said face member, a first hollow, annularchamber defined on the periphery of said back plate, and a secondhollow, annular chamber defined on the periphery of said face member,said first and second hollow chambers containing a dense fluid which isfree to move under the centrifugal forces created by blower wheelrotation.

2. Blower and fan wheel apparatus comprising, in combination, a shafthaving an axis of rotation, a plurality of annular, hollow chambersconcentric to such axis of rotation, and a plurality of blades extendingoutwardly of said shaft, one of said chambers being at least partiallyfilled with a thermoset resin, a high density filler and a low densityfiller, whereby said resin and said fillers are solidified to form acounterbalancing means, the remaining chambers being at least partiallyfilled with a dense fluid which is free to move under the centrifugalforces created by fan wheel rotation.

3. Blower and fan wheel apparatus comprising, in combination, a shafthaving an axis of rotation, a plurality of blades positioned outwardlyof said shaft and a plurality of hollow chambers concentric to such axisof rotation, at least one of said chambers being at least partiallyfilled with a mixture of thermoset resin and filler, whereby saidmixture is set to form a counterbalancing means, said remaining chamberor chambers being filled with a dense fluid which is free to move underthe centrifugal forces created by fan wheel rotation.

4. Apparatus according to claim 3 wherein said filler includes a lowdensity and a high density filler and wherein said low density fillerconsists essentially of hollow spherical particles.

5. Apparatus according to claim 4 wherein said high density fillerconsists essentially of metal particles.

6. Apparatus according to claim 3, wherein said dense fluid consistsessentially of a slurry of lead oxide in oil.

7. Apparatus according to claim 3, wherein said dense fluid comprises amixture of a fluid and high density spherical balls.

8. Apparatus according to claim 1, wherein said dense fluid comprises amixture of a fluid and high density spherical balls.

9. Apparatus according to claim 2, wherein said dense fluid comprises amixture of a fluid and high density spherical balls.

I i 4 l i

1. Blower and fan wheel apparatus comprising in combination, a hubhaving an axis of rotation, a circular back plate attached to said hub,a cover plate attached to said hub and to said back plate, said coverplate, said back plate and hub defining an annular central chamberconcentric to such axis of rotation, such chamber being at leastpartially filled with a thermoset resin, a high density filler and alower density filler, a circular face member spaced from said rearplate, a plurality of interconnecting radially positioned blades mountedbetween said back plate and said face member, a first hollow, annularchamber defined on the periphery of said back plate, and a secondhollow, annular chamber defined on the periphery of said face member,said first and second hollow chambers containing a dense fluid which isfree to move under the centrifugal forces created by blower wheelrotation.
 2. Blower and fan wheel apparatus comprising, in combination,a shaft having an axis of rotation, a plurality of annular, hollowchambers concentric to such axis of rotation, and a plurality of bladesextending outwardly of said shaft, one of said chambers being at leastpartially filled with a thermoset resin, a high density filler and a lowdensity filler, whereby said resin and said fillers are solidified toform a counterbalancing means, the remaining chambers being at leastpartially filled with a dense fluid which is free to move under thecentrifugal forces created by fan wheel rotation.
 3. Blower and fanwheel apparatus comprising, in combination, a shaft hAving an axis ofrotation, a plurality of blades positioned outwardly of said shaft and aplurality of hollow chambers concentric to such axis of rotation, atleast one of said chambers being at least partially filled with amixture of thermoset resin and filler, whereby said mixture is set toform a counterbalancing means, said remaining chamber or chambers beingfilled with a dense fluid which is free to move under the centrifugalforces created by fan wheel rotation.
 4. Apparatus according to claim 3wherein said filler includes a low density and a high density filler andwherein said low density filler consists essentially of hollow sphericalparticles.
 5. Apparatus according to claim 4 wherein said high densityfiller consists essentially of metal particles.
 6. Apparatus accordingto claim 3, wherein said dense fluid consists essentially of a slurry oflead oxide in oil.
 7. Apparatus according to claim 3, wherein said densefluid comprises a mixture of a fluid and high density spherical balls.8. Apparatus according to claim 1, wherein said dense fluid comprises amixture of a fluid and high density spherical balls.
 9. Apparatusaccording to claim 2, wherein said dense fluid comprises a mixture of afluid and high density spherical balls.